Caption: Asbestos. Computer model of a long chain silicate (polysilicate), as found in blue asbestos (crocidolite). The yellow spheres are silicon atoms, each of which is surrounded by four oxygen atoms (red) in a tetrahedral arrangement. The silicone atoms share some oxygen atoms, resulting in a chain of hexagons, which give asbestos its fibrous and resistant nature. This is a simplified model; asbestos molecules also contain other atoms such as magnesium and iron which are not shown here. Asbestos is highly toxic when inhaled as dust particles. Prolonged inhalation causes the fatal lung disease asbestosis.